|Publication number||US4271404 A|
|Application number||US 05/888,865|
|Publication date||Jun 2, 1981|
|Filing date||Mar 22, 1978|
|Priority date||Mar 29, 1977|
|Publication number||05888865, 888865, US 4271404 A, US 4271404A, US-A-4271404, US4271404 A, US4271404A|
|Original Assignee||Sharp Kabushiki Kaisha|
|Export Citation||BiBTeX, EndNote, RefMan|
|Patent Citations (6), Non-Patent Citations (1), Referenced by (14), Classifications (6)|
|External Links: USPTO, USPTO Assignment, Espacenet|
The present invention relates to an electronically controlled power supply controller for use in an electronic calculator and so on and, more particularly, to a power supply controller useful with a keyboard of the key strobing type.
A prior power supply controller for an electronic calculator is disclosed in U.S. Pat. No. 3,755,806, "CALCULATOR DISPLAY CIRCUIT" patented on Aug. 28, 1973, wherein a display circuit for use in an electronic calculator which includes a computing circuit for receiving and manipulating digital data includes means for automatically turning "off" or "blanking" the display device for the electronic calculator after a predetermined period of time between data entries. The above U.S. Patent discloses a blanking means for automatically extinguishing the display device of said electronic calculator after the lapse of a predetermined period of time.
However, power supply to the computing circuit is not controlled in the above mentioned power supply controller. It is further preferable to control the power supply for the computing circuit because the computing circuit comprising an IC consumes more power than the display device which is made of liquid crystal materials.
Accordingly, it is a broad object of the present invention to provide an improved power supply controller for an electronic apparatus.
It is a more specific object of the present invention to provide an improved power supply controller being controlled by a gate circuit for selecting a key strobe signal in response to the actuation of a predetermined key within a keyboard rather than a mechanical power switch.
Other objects and further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. It should be understood, however, that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.
To achieve the above objects, pursuant to an embodiment of the present invention, a plurality of gate circuits are provided which are responsive to both a power supply control signal and key strobe signals to initiate power supply from a power source to power a variety of circuit means, for example, a central processing unit (CPU) and a display such as a liquid crystal display and so on. The key strobe signals are generated from the CPU in a well known manner and the power control signal is developed from a power supply control circuit. The power supply is initiated upon the actuation of a specified key which is connected to the power supply control circuit so as to generate the power supply control signal. Simultaneously, numeral or command information relevant to the actuated key or keys is introduced into the CPU for manipulation purposes. The gate circuits comprise OR gate circuits and AND gate circuits. The OR gate circuits receive an inverted phase power supply control signal and the AND gate circuits receive the power control signal with the non-inverted phase in addition to the key strobe signals. A conventional mechanical power switch can be eliminated because of the above power supply control system.
Other objects and novel features of the present invention are set forth in the appended claims and the present invention as to its organization and its mode of operation will best be understood from a consideration of the following detailed description of the preferred embodiments taken in connection with the accompanying drawings, wherein:
A single drawing is a circuit diagram of a power supply controller according to the present invention.
The drawing shows a power supply controller of the present invention, wherein the numeral 1 refers to one terminal of a power source for transmitting power energy together with the other terminal (not shown) which is grounded. The numeral 2 denotes a power supply controller commprising a flip-flop circuit. The numeral 3 is a power supply controlled circuit including a central processing unit (CPU) and a display such as a liquid crystal display and so on. The numeral 4 refers to a keyboard. The power supply controller 2 is assumed to be operated by a negative voltage derived from the power source throughout the detailed description described below. A conventional mechanical power switch can be eliminated because of the function of the power supply controller for reasons which become fully apparent hereinafter.
An N-channel MOS transistor Tr is coupled to the terminal 1 and the power supply controlled circuit 3, the N-channel MOS transistor Tr being controlled by the power supply control signal P to implement the supply of power to circuit 3.
The N-channel MOS transistor Tr connects electric power from the power source to the power supply controlled circuit 3 in the ON state thereof. A plurality of both OR gate circuits L1 through Lj and AND gate circuits Lj+1 through Lm are provided for respectively conducting key strobe signals T1 through Tj and Tj+1 through Tm which are generated from the power supply controlled circuit 3. The OR gate circuits L1 through Lj also receive power supply control signal P, signal P being inverted by an inverter In. The AND gate circuits Lj+1 through Lm receive power supply controller signal P. An OR gate circuit G is connected to receive a plurality of key output signals K1 through Ki and produces an output signal which is applied to the power supply controller 2. The OR gate circuits L1 through Lj, the AND gate circuits Lj+i through Lm, the inverter In, and the OR gate circuit G are all connected to the terminal 1 to continuously receive power energy from the power source although it is not shown in the drawing.
In the aforementioned circuit configurations, the switching MOS transistor Tr connects the power supply from the power source to the power supply controlled circuit 3 when the switching MOS transistor Tr turns ON in response to the high level of the power supply control signal P. The key strobe signals T1 through Tj and Tj+i through Tm are subsequently developed from the power supply controlled circuit 3 to thereby be introduced into the OR gate circuits L1 through Lj and the AND gate circuits Lj+i through Lm, respectively.
The keyboard 4 can receive the key strobe signals T1 through Tj and Tj+i through Tm as output signals S1 through Sj and Sj+i through Sm generated from the OR gate circuits L1 through Lj and the AND gate circuits Lj+1 through Lm when the power supply control signal P bears the high level.
An actuation of a specified key included within the keyboard 4 provides a desired key output signal among key output signals K1 through Kn.
The keyboard output signals K1 through Kn are introduced into the power supply controlled circuit 3 to perform manipulation operations such as calculation functions and command instructions directed by the actuated keys.
The switching MOS transistor Tr turns OFF in response to the low level of the power supply control signal P to thereby terminate the power supply from the power source to the power supply controlled circuit 3. Therefore, the key strobe signals Tl through Tj and Tj+i through Tm become indefinite logic signal levels, respectively, namely, not definitely fixed at a level of "0" or "1".
When switching MOS transistor Tr is OFF (P at low level), all of the signals S1 through Sj bear the high levels since the inverted power supply signal P (now at high level) is introduced into the OR gate circuits L1 through Lj. On the other hand, the signals Sj+i through Sm hold all the low levels as the power supply control signal P (now at low level) is entered into the AND gate circuits Lj+i through Lm. In addition to the above, the power supply control circuit 2 receives the output signals of the OR gate circuit G which is responsive to the keyboard output signals K1 through ki.
Under these circumstances wherein the power supply from the power source to the power supply controlled circuit 3 is excluded, a selected key included within the keyboard 4 is actuated to initiate the power supply, the key selection being related to the combination of both the signal S1 and anyone of the key output signals K1 through Ki or the signal S2 and anyone of the key output signals K1 through Ki. In response to either one of the above combination output signals of the OR gate circuit G change to the high level, whereby the power supply control signal P is recovered to the high level to thereby provide the power supply from the power source to the power supply controlled circuit 3. The key output signals K1 through Kn are simultaneously introduced into the power supply controlled circuit 3 to provide numerical or command information corresponding to the respective key.
In contrast, the supply of power can not be initiated when the keys are actuated such that the signal Sj+1 is combined with the key input signals K1 through Ki or the signal Sj+2 is combined with the key output signals K1 through Ki, because the output signals of the OR gate circuit G can not be changed to the high level owing to the low levels of the output signals Sj+1 through Sm.
The AND gate circuits Lj+1 through Lm are required to hold the low level of the output signals Sj+1 through Sm without regard to the indefinite levels of the key strobe signals Tj+1 through Tm.
The termination of the power supply from the power source to the power supply controlled circuit 3 is achieved by allowing the power supply control signal P to achieve the low level in response to the actuation of a different power-off switch formed within the keyboard 4 or the lapse of a predetermined time after the actuation of any key included within the keyboard 4.
The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications are intended to be included within the scope of the following claims.
|Cited Patent||Filing date||Publication date||Applicant||Title|
|US3641328 *||May 21, 1969||Feb 8, 1972||Hewlett Packard Co||Keyboard entry means and power control means for calculator|
|US3946216 *||Sep 24, 1973||Mar 23, 1976||Texas Instruments Incorporated||Electronic calculator system having serial transfer of instruction word fields to decode arrays|
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|Citing Patent||Filing date||Publication date||Applicant||Title|
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|US4812831 *||Feb 10, 1987||Mar 14, 1989||Amp Incorporated||Key switch with controllable illumination|
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|US9537324||Dec 10, 2012||Jan 3, 2017||Fleetwood Group, Inc.||Audience response system with batteryless response units|
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|WO1994009477A1 *||Oct 15, 1993||Apr 28, 1994||Brien Cathy Mishek O||Ergonomic keyboard and operator's chair|
|U.S. Classification||341/26, 713/321|
|International Classification||G05F1/10, G06F1/26|